From 800b85c850e9ed1dda183630125f620ddaa3f265 Mon Sep 17 00:00:00 2001
From: Stu Small <stuart.alan.small@gmail.com>
Date: Mon, 29 Apr 2019 20:13:37 -0600
Subject: [PATCH] Add param parsing fuzzer and fix finding

---
 hfuzz/Cargo.toml        |  4 ++--
 hfuzz/src/bin/params.rs | 15 +++++++++++++++
 src/params/patterns.rs  |  6 ++++--
 3 files changed, 21 insertions(+), 4 deletions(-)
 create mode 100644 hfuzz/src/bin/params.rs

diff --git a/hfuzz/Cargo.toml b/hfuzz/Cargo.toml
index 7e994f9d..c821148f 100644
--- a/hfuzz/Cargo.toml
+++ b/hfuzz/Cargo.toml
@@ -4,6 +4,6 @@ version = "0.1.0"
 authors = ["Jake McGinty <me@jake.su>"]
 
 [dependencies]
-honggfuzz = { git = "https://github.com/mcginty/honggfuzz-rs", branch = "assert-unwind" }
+honggfuzz =  "0.5"
 snow = { path = "../" }
-lazy_static = "*"
\ No newline at end of file
+lazy_static = "*"
diff --git a/hfuzz/src/bin/params.rs b/hfuzz/src/bin/params.rs
new file mode 100644
index 00000000..42ccbb3f
--- /dev/null
+++ b/hfuzz/src/bin/params.rs
@@ -0,0 +1,15 @@
+#[macro_use] extern crate honggfuzz;
+extern crate snow;
+
+fn main() {
+    loop {
+        fuzz!(|data: &[u8]| {
+             if let Ok(s) = String::from_utf8(data.to_vec()){
+                if let Ok(p) = s.parse(){
+                    let builder = snow::Builder::new(p);
+                    let _  = builder.build_initiator();
+                }
+            }
+        });
+    }
+}
\ No newline at end of file
diff --git a/src/params/patterns.rs b/src/params/patterns.rs
index b64b4908..2b4cb0b5 100644
--- a/src/params/patterns.rs
+++ b/src/params/patterns.rs
@@ -222,8 +222,10 @@ impl HandshakeChoice {
     fn parse_pattern_and_modifier(s: &str) -> Result<(HandshakePattern, &str), Error> {
         for i in (1..=4).rev() {
             if s.len() > i-1 {
-                if let Ok(p) = (&s[..i]).parse() {
-                    return Ok((p, &s[i..]));
+                if s.is_char_boundary(i) {
+                    if let Ok(p) = (&s[..i]).parse() {
+                        return Ok((p, &s[i..]));
+                    }
                 }
             }
         }